Apparatus for reflecting light-rays.



A. H. ADAMS.

APPARATUS FOR REFLECTING LIGHT RAYS.

APPLICATION FILkD JAN-14,1915.

1 32397520 Patented Apr. 24,1917.

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A. H. ADAMS.

APPARATUS FOR REFLECTING LIGHT RAYS.

APPLICATION FILED JAN. l4. I9I5.

Patented Apr. 24, 1917.

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ARTHUR H. ADAMS, OF SPARKILQ, NEW YORK, ASSIGNOR, BY MESNE ASSIGNMENTS, T0 WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION OF NEW YORK.

APPARATUS FOR REFLECTIN G LIGHT-RAYS.

Specification of Letters Pate nt.

Patented Apr. 24,1911

Application filed January 14, 1915. Serial No. 2,181.

To all whom it may; concern:

Be it known that I, ARTHUR H. ADAMS, a citizen of the United States, residing at Sparkill, in the county of Rockland and State of New York, have invented certain new and useful Improvements in Apparatus for Reflecting Light-Rays, of which the following is a full, clear, concise, and exact description.

This invention relates to the reflection of light rays, and has for its object to provide an apparatus for confining substantially all of the light rays from a source to a given area.

In accordance with the general features of this invention, the source of light is located in substantially the common focus of reflecting paraboloids of difi'ering focal lengths, and an opening is provided in the reflecting surface having the greater focal length for the passage of light rays.

In the drawings in which the invention is shown in connection with an incandescent electric lamp,

Figure 1 is a sectional view of an evacuated globe inclosing the filament and having itslsurfaces coated with a reflecting materia Fig. 2 shows a scheme in which the filament is inclosed in a small bulb surrounded by the reflecting surfaces; and

Fig. 3 shows the filament inclosed within a large bulb also containing the reflecting surfaces.

Referring to the drawings and particularly Fig. 1, 5 designates an ordinary screw base adapted to fit into any of the ordinary incandescent lamp sockets. 6 designates a filament which is connected by lead wires 7 and 8 to the contacts of the base in the ordinary way. Surrounding the filament 6 is an evacuated globe comprising parabolic members 9 and 10 of widely differing focal lengths struck about a common focus which is preferably the exact geometrical center of the filament. The parabolic member 9, which has the smaller focal length, partially surrounds the filament 6 and is coated over its entire surface with a material forming a reflecting surface 15. The parabolic member 10 having the greater focal length is located in opposition to the member 9, and is also provided with a reflecting surface 16 which covers all of said member, except a small portion 17 opposite the filament 6 through which the light rays from the filament 6 may pass. A lens 18 may be located opposite the opening 17.

In the modification shown in Fig. 2, the filament 6 is located within a small bulb 20 which in turn is located within parabolic refleeting surfaces 21 and 22 bearing the same relation to the filament 6 as do the reflecting surfaces 15 and 16 in Fig. 1.

In Fig. 3 the reflecting surfaces '21 and 22 of Fig. 2, within which the filament 6 is located, are themselves located within an evacuated bulb 25.

By the use of this invention it will be seen that all of the light rays emanating from the filament 6 will eventually be reflected out through the opening 17. The small amount of light lost will be by absorption in reflection and those rays which will strike the filament upon passing the focal point.

Perhaps the worst case of reflection would be the case illustrated by broken lines in Fig.1, in which a light ray from the filament 6 following the line 30 will strike the reflecting surface 16 near the opening 17, will be reflected back to the surface 15 along the line 31, will be reflected from the surface 15 through the focus along the line 32, and striking the surface 16 toward the lower margin thereof will be reflected back along the line 33 to the surface 15, striking it near the upper margin thereof from which it will be reflected along the line 34 through the focus striking the surface 15 upon the opposite side of the filament 6. From this point it will take the path and direction of the line 35, striking the surface 16 about midway between the edge of the opening 17 and the margin of the surface 16 from where it will be reflected back along the line 36 through the focus to the surface 15, and from there out through the opening 17 along the line 37.

What is claimed is:

1. In a light projecting device, 'a source of light and means for projecting. substantially all the rays from said source upon a limited area, said means comprising a'pair of reflecting paraboloids of different focal length arranged in opposing relation on a common axis and having said source of light as a common focus, one of said paraboloids the passage of light rays.

2. In a light projecting device, a source i of light and means for projecting substantially all the rays from said source upon a limited area, said means comprising a pair 'of reflecting paraboloids of different focal length arranged in opposing relation on a common axis and having said source of light as a common focus, the paraboloid of greater -focal length being provided with an axial opening for the passage of light rays.

3. In a light projecting device, a source of light, a parabolic reflector partly surrounding said source of light and having its focus substantially coincident with the effective center of said source, a second parabolic reflector of greater focal length than the first arranged on the other side of said source of focus substantially coincident with the e ective center of said source, a second parabolic reflector of greater focal length than the first arranged on the other side of said source of light in opposing relation to said firstmentioned parabolic reflector, and having a common axis and focus therewith; said reflectors being arranged in abutting relation, the reflector of greater focal length having an axial opening for the passage of light rays.

5. An electric lamp comprising a front and rear wall joined together, both walls being of paraboloidal contour arranged on a common axis in opposing relation, said wall contours being of different focal length and having the focus of one coincident with the focus of the other, a filament mounted at said coincident focus, a paraboloidal reflecting surface on one of said walls, and an annular reflecting surface on the other of said walls. v

6. An electric lamp comprising a rear wall of paraboloidal contour, a concentrated filament mounted at the focus of said paraboloidal contour, a front wall of a paraboloidal contour of different focal length from that of the rear wall and arranged in opposing relation thereto on a common axis, the focus of one being coincident with the focus of the other, a paraboloidal reflecting surface on one of said walls, and an annular reflecting surface on the other of said walls concentric with said common axis, said walls being joined together and inclosing said filament.

In witness whereof I hereunto subscribe my name this 13th day of January, A. 1)., 1915.

ARTHUR H. ADAMS.

Witnesses:

E. EDLER, K. L. STAHL. 

